Leach joined the Kings following three seasons as an assistant coach with the University of Maine from 1984-86 and again in 1987-88. Leach began his NHL coaching career with Hartford, spending three seasons as an assistant on the Whalers’ staff from 1988-91.

Leach then spent five seasons as a head coach in the American Hockey League, guiding the Springfield Indians for two seasons in 1991-93 before taking over the Hershey Bears. In Springfield, Leach’s teams won the AHL Northern Division in 1991-92 and the conference playoff championship in 1992-93, while he won the AHL Southern Division in his first season with Hershey in 1993-94. As a head coach, Leach led his AHL teams to the playoffs each year, compiling a 140-137-43

Following his time with the Kings, Leach was as an assistant coach for the New Jersey Devils in the 2001-02 season and worked as an assistant coach for the Atlanta Thrashers during the team’s first two seasons in the league, 1999-2001. He was an assistant coach for the Capitals from Dec. 16, 2003 - the end of the 2009 Stanley Cup Playoffs.

Leach has international coaching experience as well. He was selected to be an assistant coach for the U.S. Men’s National Team at the 2004 World Championship in the Czech Republic and the 2006 World Championship in Latvia. Leach and head coach Peter Laviolette guided the 2004 United States team to a bronze medal.

Leach also served as an assistant coach under Bob Johnson with Team USA at the 1991 Canada Cup, winning a silver medal. A former center in the Quebec Nordiques and Minnesota North Stars systems during his playing career, Leach has also worked as a scout in the New York Islanders’ organization.